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flat assembler > Non-x86 architectures > [fasmarm] arm mov instruction

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Ptarmigan



Joined: 29 Jul 2010
Posts: 4
Why does
mov r9,0xff00
work while
mov r9,#0xff,8

not work? they both both have to shift the 8 bit immediate value left as the instruction runs......
Any time I add a third parameter I get this error:

error: Third parameter is invalid.

Shocked

fozzie
Post 03 Sep 2010, 22:49
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 16578
Location: Earth 2.0 beta
fasmarm does not support a third parameter for mov. Do you think I should add it? I've never seen anyone use it before.

Although be careful, the shift is actually a right rotation. So it should be mov r9,0xff,24
Post 04 Sep 2010, 00:43
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Ptarmigan



Joined: 29 Jul 2010
Posts: 4
revolution wrote:
fasmarm does not support a third parameter for mov. Do you think I should add it? I've never seen anyone use it before.

Although be careful, the shift is actually a right rotation. So it should be mov r9,0xff,24


you should add or document that it is missing in the compatibility section. As I understand it mov is to the left and mvn is to the right, but I may have it backwords....

mov and the missing pseudo-intructions are the two biggest things I tripped over in learning fasmarm. Most of the text books I have on arm use the 3 parameter form.... I think the explicit form reinforces the instruction's limitation better.

thanks
Post 04 Sep 2010, 01:15
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
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mov is a direct move.
mvn is an inverted move.

And the shift is a right-rotation, always, for both mov and mvn.
Post 04 Sep 2010, 01:30
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Tyler



Joined: 19 Nov 2009
Posts: 1216
Location: NC, USA
Ptarmigan wrote:
Most of the text books I have on arm use the 3 parameter form.... I think the explicit form reinforces the instruction's limitation better.
IIRC, revolution convinced ARM to open up some docs. Although I'm not too much of a manual reader either, you may find it helpful. You have to register though...

Links can be found at arm.flatassembler.net, if you can bare revolution's web page long enough to find them Razz.Seriously though, I would so fix that for you. I had a class in web design last year. It's nice to take a break from algorythmic thinking every once in a a while.
Post 04 Sep 2010, 04:31
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
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Tyler wrote:
Seriously though, I would so fix that for you.
I didn't realise it was broken. Thanks for pointing it out, I have now fixed the links.
Post 04 Sep 2010, 04:39
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Tyler



Joined: 19 Nov 2009
Posts: 1216
Location: NC, USA
No, I meant your page sucks... Razz The links are and were correct.
Post 04 Sep 2010, 04:57
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 16578
Location: Earth 2.0 beta
Tyler wrote:
No, I meant your page sucks...
I'm not much into graphical design stuff. Maybe you already guessed that. Wink
Post 04 Sep 2010, 05:01
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Tyler



Joined: 19 Nov 2009
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I noticed your source is very linear, much like asm. I'm guessing that's probably not a coincidence.

Edit: For someone not into web design, you know standards pretty well. You'd be surprised how many people in my class, at a community college, couldn't figure out that it's <br /> not <br>. Even the professor used <br> in all his examples.
Post 04 Sep 2010, 05:10
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ass0



Joined: 31 Dec 2008
Posts: 521
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<br> is for SGML (HTML), while <br/> is XML compliant (XHTML).

Did you pay to learn web design?
Anyway i think i am so used to only pay for internet as a source of knowledge that everything else seems to me, a waste of money. =D

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Nombre: Aquiles Castro.
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Post 04 Sep 2010, 05:50
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Tyler



Joined: 19 Nov 2009
Posts: 1216
Location: NC, USA
> <br> is for SGML (HTML), while <br/> is XML compliant (XHTML).
Okay, you got me. I was an entry level course. Embarassed But to be fair, the class was all about XML and XSLT. See.

> Did you pay to learn web design?
I would've had to pay if I weren't in HS. The college has an agreement with my HS to let us take college classes for free.

Quote:
Anyway i think i am so used to only pay for internet as a source of knowledge that everything else seems to me, a waste of money. =D
I agree. It seem backwards to me how academia validates knowledge and experience. There should be accepted alternative to spending money and time to get a piece of paper saying you know what knew before you took the class.
Post 04 Sep 2010, 14:53
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 16578
Location: Earth 2.0 beta
I have updated fasmarm to support the byte,rotation syntax in v1.17
Post 08 Sep 2010, 11:44
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Ptarmigan



Joined: 29 Jul 2010
Posts: 4
thanks a bunch!
Post 08 Sep 2010, 20:43
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 16578
Location: Earth 2.0 beta
Just to be clear, the op reg,byte,rot and op reg,reg,byte,rot syntax is only valid in ARM mode and is valid for all the following functions:

adc, add, and, bic, cmn, cmnp, cmp, cmpp, eor, mov, mvn, orr, rsb, rsc, sbc, sub, teq, teqp, tst, tstp

See the file "\ARMDOC\InstructionFormatsARM.asm" for the examples of how and where it can be used.
Post 09 Sep 2010, 04:36
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